Castors, particularly in the form of swivel castors

ABSTRACT

A castor, particularly in the form of a swivel castor, is provided with a locking mechanism for locking the running wheel against running and/or swivelling movement. The locking comprises as locking member a press component which is axially moveable in a guide bush arranged at the castor fork. The press component can be pressed against the pressure of a spring into its locking position and then holds the locking mechanism in its locking position. The press component has at a point on its periphery at least one latching notch by means of which the press component can latch in its locking position under the counterpressure of the spring against a latching edge and is then held latched by the stressed spring. A release lever is provided by which the press component can be unlatched again, against the pressure of the spring. The guide bush may be arranged substantially vertically at the castor fork, and the press component notched on its periphery may project beyond the upper surface of the guide bush and may form a pushbutton for foot actuation.

United States Patent 1 [111 3,772,733

Stosberg et al. Nov. 20, 11973 [54] CASTORS, PARTICULARLY IN THE FORM 2,684,734 7/1954 Wilson 16/35 OF SWIVEL CASTORS [75] Inventors: Herbert Stosberg, Primary Examiner-James T. McCall Wermelskirchen-Tente/Rheinland; Assistant Examiner-Doris L. Troutman Giinter Reinhards, Attorney-Burgess, Dinklage & Sprung Wermelskirchen/Rheinland; Siegfried Engels,

Wermelskirchen-Tente/Rheinland; [5 7] ABSTRACT Hans-Jiirgen Sauer, wermelSkirchen/Rheinland, an of A castor, particularly n the form of a swivel castor, is Germany provided with a locking mechanism for locking the running wheel against running and/or swivelling movel Assigneer Firm Tulle-Rout?" Geseuscha mil merit. The locking comprises as locking member a beschl'ankml' flaming Compagnie, press component which is axially moveable in a guide welmelskil'chefl-Tente/Rhein1and, bush arranged at the castor fork. The press compo- Germany nent can be pressed against the pressure of a spring [22] Filcd; Jam 28 1972 into its locking position and then holds the locking mechanism in its locking position. The press compo- PP N04 221,559 nent has at a point on its periphery at least one latching notch by means of which the press component can latch in its locking position under the counterpressure [30] Foreign Application Priority Data of the spring against a latching edge and [S then held Feb. 27, 1971 Germany P 21 09 458.6 latched y the stressed p g A release lever is p vided by which the press component can be unlatched 5%] 8L... again, against the pressure of the spring The guide Fie'ld "16/35 35 bush may be arranged substantially vertically at the 1;;8/1 castor fork, and the press component notched on its periphery may project beyond the upper surface of the [S 6] Reierences Cited guide bush and may form a pushbutton for foot actuation. UNITED STATES PATENTS 3,571,842 3/1971 Dietrick Fricke 16/35 17 Claims, 6 Drawing Figures 4' t r/ 1 9 l v PMENTEDNDY 20 I975 SHEET 5 BF 6 CASTORS, PARTICULARLY IN THE FORM OF SWIVEL CASTORS This invention relates to a castor with a locking mechanism for locking the running wheel. in the case of a stationary castor, the locking mechanism serves to lock the running wheel to prevent it running. In the case ofa swivel castor with a swivellable running wheel, then the locking mechanism can be designed to lock the running wheel so as to prevent it from swivelling, instead. In the case of a swivel castor the locking mechanism can however also serve for locking the running wheel both in respect of its running movement and also in respect of its swivelling movement.

With such castors, and particularly swivel castors, the locking mechanism comprises a locking member, generally supported in the fork hollow, and which for the purpose of locking the running wheel against running movement, is pressed in a suitable manner against the wheel tyre, and/or for locking the running wheel against swivelling movement is brought into engagement 'for instance with teeth on a fixed ball bearing shell of the castor holding system. The locking member, which may consist for instance of a stable leaf spring or of a one-armed or two-armed swivel lever, can be brought in the case of known forms of construction by means of a foot shift lever provided on the eastor, into its locking position and again into its released position, as desired. This can be effected by actuating the foot shift lever with the point of the foot, the said foot shift lever being depressed to lock' the castor, and raised for the unlocking, by the point of the foot. The

raising of the foot shift lever by means of the point ofthe foot is however an operation calling for care, and leads, particularly in the case of hospital furniture fitted with such lockable castors, to damage of the light footwear of the hospital personnel, particularly the remale personnel.

Castors have therefore already been proposed with a locking mechanism in which both the locking and also the subsequent unlocking of the castor can be effected by successive depressions of the foot shift lever. For

this purpose there is provided in the locking mechanism a ratchet wheel, which, each time the foot shift lever is depressed, is rotated onward by one ratchet tooth, and thus acts on the locking member supported in the fork hollow, to lock and release it alternately. However, a locking mechanism constructed in this way necessitates a high degree of accuracy of finish of the ratchet mechanism. Furthermore, such a shift arrangement, because of the restricted space available, cannot be completely accommodated in the castor fork, which means that castors constructed in this way hardly have a pleasant appearance, although for use as lockable furniture castors or appliance castors, such a pleasant appearance is important.

To avoid these disadvantages, castors, and particucan be pressed against the action of s spring into its locking position, and then holds the locking mechanism in its locking position, as described and explained in German Gebrauchsmuster No. l 960 139 and US. Pat. No.3 571 842 (U.S. Pat. application Ser. No. 695 942) for which the application was filed on the 5th Jan. 1968.

Such a press alternating shift mechanism admittedly works accurately and satisfactorily, but a peak quality product of fine engineering is here involved. It could therefore only be economically used for castors, which are relatively cheap mass-produced articles, if the detailed components of the press alternating shift mechanism are produced in very large number and the castors to be fitted with it likewise have a highly accurate finish. In the field of castors however there are many types which are produced only in small numbers. There are also many castors which are of a simple construction and in which, because of the inaccuracies in the whole roller construction and in the tyre diameter, it is only seldom that maximum effectiveness of the locking mechanism can be attained, when this is fitted with a high-accuracy press alternating shift mechanism as the locking and detent member. An object of the invention is to avoid these disadvantages and to provide a locking mechanism for castors, consisting of a minimum number of indivudual components, the production of which is as simple as possible and is economic even with a small number of components, in which furthermore large finish tolerances do not affect, or only slightly affect the working of the device, and which in case of need can also be applied subsequently to existing cas tors, without a special degree of accuracy in fitting having to be observed.

The new castor, which in paticular may be a swivel castor, and which is provided with a locking mechanism for locking the running wheel against running and/or swivelling movement, and which has as the locking member a press component, which is axially moveably in a guide bush provided at the castor fork, and which can be pressed against the action of a spring into its locking position, and then holds the locking mechanism in its locking position, is characterised in accordance with the basic idea of the invention that the press component has at a point on its periphery, a catch or latching notch by means of which the press component can be latched in its locking position by the counterpressure of the spring against a latching edge and is then held latched by the stressed spring, and in that a release lever is provided by which the press component can subsequently be unlatched against the pressure of larly swivel castors, have already been proposed with a the spring. Such a locking and detent mechanism consists of only a few components which are simple to produce and it is still reliable in operation even when the swivel castors and stationary castors, and particularly their running wheels, which are to be locked, have coarse production tolerances. Such a locking and detent mechanism can also be produced subsequently by simple means and fitted if requisite to castors already in use.

The guide bush with the press component actually moveable therein and notched at a point on its periphery, can be arranged in the locking mechanism of the castor in various suitable ways. It is particularly advantageous howwver to have a castor, particularly a swivel castor, in which the guide bush is arranged essentially vertically to the castor fork, and in which the press component notched at its periphery projects beyond the upper surface of the guide bush and forms a pushbutton, which can be actuated with the point of the foot. Such a pushbutton actuation is very simple and cheap to produce and still gives the castor a pleasing appearance even in the case of a swivel castor.

In accordance with a modification of the basic idea of the invention the press component can have at a point on its periphery a multiplicity oflatching notches, which are arranged one above the other in the axial direction of the press component. This makes it possible to vary the depth at which the notched press component, continuously under the counterpressure of the spring, latches or catch-engages in its guide bush, by exerting a more powerful pressure. Owing to this feature the locking and detent member in accordance with the invention is capable of bridging over particularly large inaccuracies in the construction and finish of swivel castors and stationary castors and particularly in the tyre diameter of the running wheels, and makes it possible to attain maximum efficiency of the locking mechanism even when the tyre of the running wheel has become considerably worn after long use.

Although the notched press component may be of any form desired, it is particularly advantageous from the point of view of production technique, if it is cylindrical. In order in this case to avoid the need for precautions to ensure that the notched point of the cylindrical press component is always turned towards the latching edge at which the press component can latch fast when pressed into its guide bush, the cylindrical press component may be provided with one or more catch or latching notches arranged around the periphery of the cylinder. The peripherally notched cylindrical press component may then rotate as desired in its guide bush and is still capable in any position of latching at the latching edge. This has furthermore the advantage from the point of view of production technique that the latching notch or multiplicity of latching notches in the press component can simply be machined on a lathe.

The notched press component axially moved in its guide bush then latches or hooks against the latching edge through the counterpressure of the spring particularly powerfully and securely fast if the latching notch or multiplicity of latching notches of the press component are given a sawtooth form, that is to say in such a way that a radially straight tooth flank serves for the latching against the latching edge.

It is an advantage if the notched press component is fixed on a counterpressure leaf spring, which may simultaneously be that part of the locking mechanism which is pressed against the wheel tyres to lock the running wheel to prevent it running. The notched press component is thereby held fast but axially moveable in its guide bush, which permits constructional components which are simple to form and economic to produce.

In a preferred embodiment of the invention the notched press component is made substantially narrower than the guide hole of its guide bush and it has therefore so large a lateral play in the guide bush that it can tip by the counterpressure of the spring in its guide bush and thus can latch better by one of its latching notches against the latching edge. In this case the latching edge for the latching of the press component can be formed in a simple manner'by the lower latching edge of the guide hole of the guide bush. To unlock the locking mechanism the press component may be provided with a foot lever which serves as a release lever for unlatching the press component again. In this connection the press component can simply be fixed to the foot lever which serves as a release lever unlatching the press component, and the foot lever can have an oblique surface which when the press component is pressed down comes to rest against a counterpressure leaf spring and thereby favours the tipping of the press component for its easier latching against the latching edge.

In another embodiment of the invention the latching edge which serves for latching the notched press component, is formed by a latching leaf spring which can latch in one of the latching notches of the press component. The latching leaf spring can in this case be extended to form a foot pedal, which also serves as a release lever for unlatching the press component.

In a further embodiment of the invention the press component axially moveable in a guide bush, instead of having a direct notching, may have at its periphery a resilient latching pawl which can latch against a latching edge when the press component has been pressed into its locking position. In order in this case again to be able to bridge over large inaccuracies in the construction and finish of the swivel castor or stationary castor and also to be able to maintain maximum efficiency of the locking mechanism, even after wear of the running wheel tyre, the latching pawl may likewise be provided with a multiplicity of latching notches arranged one above the other. The latching pawl of the press component may be provided with a foot pedal which acts as a release lever for unlatching the press component.

Specific embodiments of the invention will now be described by way of example with reference to the accompanying drawings, which show swivel castors in which only the running movement ofthe running wheel can be locked, although it will be obvious that it is also possible for the swivel castors to be formed as completely lockable swiven castors.

In the drawings:

FIG. 1 shows in part vergical section a castor with a locking mechanism in the release position in which the notched press component can be tipped or canted in its guide bush,

FIG. 2 shows in part vertical section the castor of FIG. 1 with the locking mechanism in its locking position,

FIG. 3 shows in part vertical section a castor with a locking mechanism in the release position, in which the latching edge for latching the notched press component is formed by a sprung foot pedal,

FIG. 4 shows in part vertical section the castor of FIG. 3 with the locking mechanism in its locking position,

FIG. 5 shows in part vertical section a castor with a locking mechanism in the release position, in which the press component has a notched latching pawl, and

FIG. 6 shows in part vertical section the castor of FIG. 5 with the locking mechanism in its locking position.

In the exemplary embodiments illustrated the castors in question are swivel castors, in which the running wheel 1 is supported in a castor fork 2 which can swivel round an off-set bearing 3. The swivel castors have a locking mechanism which in the embodiments represented, serves only to lock the running wheel 1 to prevent it from running. As a brake element there is used a curved leaf spring 4 which is connected by two rivets or screws to the castor fork 2. The locking mechanism can instead, or additionally, also be constructed so as to lock the castor fork 2 and hence the running wheel 1, against the possibility of swivelling. For this purpose instead of the leaf spring 4 in the hollow of the castor fork 2 a locking rocker in the form of a twoarmed bilateral lever may be supported on a transverse spindle, latching by one latching edge in ratchet teeth on the inner spherical surface of the off-set bearing 3 and thus able to lock the fork 2 so as to prevent it swivelling.

At the same time a bearing component 6 is fixed to the castor fork 2 by means of rivets 5. This bearing component carries a guide bush 7 in which a press component 8 is axially moveable as the locking member. The press component 8 can be pressed into its locking position against the pressure of the leaf spring 4 in order to hold the locking mechanism in its locking position. The guide bush 7 is arranged substantially vertically by means of the bearing component 6 at the castor fork 2. The press component 8 projects beyond the upper edge of the guide bush 7 and forms a pushbutton 10, which can be actuated by the point of the foot. In the embodiments illustrated the press component 8 formed as a pusbutton is cylindrical.

In the embodiment shown in FIGS. 1 and 2 the press component 8 has at a point 11 on the pheriphery trailing the running wheel 1, a multiplicity of latching notches 12 arranged axially one above another. In this way it is possible for the press component 8 formed as a pushbutton, when depressed by the point of the foot against the pressure of the leaf spring 4, to latch against a latching edge 13, which in this embodiment is formed by the lower latching edge 14 of the guide hole 15 of the guide bush 7. In order to render the latching possible, in this embodiment the press component 8 is made substantially narrower than the guide hole 15 of the guide bush 7, so that the press component 8 has a sufficiently large lateral play to be able, under the counterpressure exerted by the leaf spring 4, to cant somewhat laterally in the guidebush 7 and in this way it is possible for it to latch by one of its latching notches 12 against the lower latching edge 14 of the guide hole 15 of the guide bush 7 (FIG. 2). The latching is effected by the counterpressure which the-leaf spring 4 exerts on the canted press component 8 in its locking position. In order to ensure a secure latching, the latching notches 12 are in sawtooth form, the radially straight tooth flank being directed upwards and serving for the latching against the latching edge 13. In this embodiment the press component 8 is fixed to a foot pedal 16 which has an oblique surface 17 which when the press component 8 is depressed comes to rest against the counterpressure spring 4 and thus favours the lateral canting of the press component 8 and hence its secure latching against the latching edge 13. The foot pedal 16 which is equipped with the press component 8, serves as a release lever for the unlatching of the press component 8, for the purpose of unlocking the locking mechanism. When the press component 8 is in its locking position (FIG. 2) and a pressure is then exerted on the foot pedal 16 with the point of the foot, the canted press component 8 can be brought back again into its normal position parallel to the axis and thus unlatched, so that it can travel back quickly under the pressure of the leaf spring 4 into its starting position (FIG. 1).

In the embodiment shown in FIGS. 3 and 4 the cylindrical press component 8 has a multiplicity of latching notches 12 arranged round the cylinder periphery 18. In this embodiment the latching edge 13 is formed by a latching leaf spring 19 which is conjointly fixed by means of rivets 5 in the hollow of the castor fork 2. If

an axial pressure is exerted on the press component 8 with the point of the foot then the said press component 8 moves against the pressure of the leaf spring 4, which serves as a brake element for locking the running wheel 1 to prevent it from running, downwards in its guide bush 7. This means that the latching edge 13 of the leaf spring 19 can latch in one of the latching notches 12 provided round the cylinder periphery l8 and thus hold the press component 8 firmly and securely in its locking position (FIG. 4). The free end of the latching leaf spring 18 is extended to form a foot pedal 16 which acts as a release lever for the unlatching of the press component 8 with the object of unlocking the locking mechanism. When the press component 8 is in its lower locking position (FIG. 4) and a pressure is exerted with the point of the foot on the foot pedal 16, then the latching edge 13 of the latching leaf spring 19 springs out of the latching notches 12 of the press component 8 and leaves this free again. This means that the press component 8 can travel quickly back into its starting position under the pressure of the leaf spring 41,, so that the locking mechanism is again unlocked (FIG. 3). To ensure that the press component 8 does not escape from its guide bush 7 during this rapid travelling back, the said press component 8 has a lower pin 20, by which it is fixed and firmly riveted to the counterpressure leaf spring 4.

In the embodiment shown in FIGS. 5 and 6 the cylindrical press component 8 formed as a pushbutton has at a point on its periphery 11 trailing the running wheel 1 a latching pawl 21, which is supported by means of a pin 22 so as to be able to move in an axially extending groove 23 of the press component 8. The latching pawl 21 is under pressure from a small leaf spring 24 which tends to press the latching pawl 21 continuously outwards. The sprung latching pawl 21 has outwardly a multiplicity of latching notches 12 arranged one above another. when the press component 8 is pressed downwards by the point of the foot in the guide bush 7 against the pressure of the leaf spring 4 then the sprung latching pawl 21 can move radially outwards. This means that the said latching pawl 21 can latch by one of its latching notches 12 against a latching edge 13 which is formed by the lower rim edge 14 of the guide hole of the guide bush 7 (FIG. 6). Because of the pressure exerted by the two leaf springs 4i and 24 the press component 8 is then securely held fast in its lower locking position. The latching pawl 21 of the press component 8 is provided with a foot pedal 16 which serves as a release lever for the unlatching of the press component 8 with the object of unlocking the locking mechanism. When the said press component 8 is located in its lower locking position (FIG. 6) and a pressure is then exerted by the point of the foot on the release lever 16, in this way the pawl 21 is again unlatched against the pressure of its spring 24 and thus the press component 8 is free again. Under the pressure of the leaf spring 4 the said press component 8 rapidly travels back into its upper starting position, so that the locking mechanism is unlocked again. To prevent the press component 8 from leaving its guide bush 7 during this rapid travelling back, it is fixed and riveted fast by a lower pin 20 to the leaf spring 4.

What we claim is:

1. A castor, particulary in the form of a swivel castor, comprising a castor fork with a running wheel and a locking mechanism for locking said running wheel against a movement, including as locking member a press component which is axially moveable in a guide bush arranged at the castor fork and which can be pressed against the pressure of a spring into its locking position and then holds the locking mechanism in its locking position, characterised in that the press component has at a point on its periphery at least one latching notch by means of which the press component can latch in its locking position under the counterpressure of the spring against a latching edge and is then held latched by the stressed spring, and in that a release lever is provided by which the press component can be unlatched again, against the pressure of the spring.

2. A castor as claimed in claim I, particularly in the form of a swivel castor, comprising a castor fork with a running wheel and a locking mechanism for locking said running wheel against a movement, including as locking member a press component which is axialy moveable in a guide bush arranged at the castor fork and which can be pressed against thepressure of a spring into its locking position and then holds the locking mechanism in its locking position, characterised in that the guide bush is arranged substantially vertically at the castor fork and the press component projects beyond the upper surface of said guide bush and forming a pushbutton for foot actuation, and in that the press component has at a point on its periphery at least one latching notch by means of which the press component can latch in its locking position under the counterpressure of the spring against a latching edge and is then held latched by the stressed spring, and in that a release lever is provided by which the press component can be unlatched again, against the pressure of the spring.

3. A castor as claimed in claim 1, particularly in the form of a swivel castor, comprising a castor fork with a running wheel and a locking mechanism for locking said running wheel against a movement, including as locking member a press component which is axially moveable in a guide bush arranged at the castor fork and which can be pressed against the pressure of a spring into its locking position and then holds the locking mechanism in its locking position, characterised in that the press component has at a point on its periphery at least one latching notch by means of which the press component can latch in its locking position under the counterpressure of the spring against a latching edge, and in that the press component is substantially narrower than the guide hole of said guide bush and has a sufficiently large lateral play for it to be able to be canted in said guide bush by the counterpressure of the spring and thus for it to be possible to latch by said at least one latching notch against the latching edge and is then held latched by the stressed spring, and in that a release lever is provided by which the press component can be unlatched again, against the pressure ofthe spring.

4. A castor as claimed in claim 2, particularly in the form of a swivel castor, comprising a castor fork with a running wheel and a locking mechanism for locking said running wheel against a movement, including as locking member a press component which is axially moveable in a guide bush arranged at the castor fork and which can be pressed against the pressure of a spring into its locking position and then holds the locking mechanism in its locking position, characterised in that the guide bush is arranged substantially vertically at the castor fork and the press component projects beyond the upper surface of said guide bush and forming a pushbutton for foot actuation, and in that the press component has at a point on its periphery at least one latching notch by means of which the press component can latch in its locking position under the counterpressure of the spring against a latching edge, and in that the press component is substantially narrower than the guide hole of the guide bush and has a sufficiently large lateral play for it to be able to be canted in said guide bush by the counterpressure of the spring and thus for it to be possible to latch by said at least one latching notch against the latching edge and is then held latched by the stressed spring, and in that a release lever es provided by which the press component can be unlatched again, against the pressure of the spring.

5. A castor as claimed in claim 1, characterised in that the press component has at a point on its periphery a multiplicity of latching notches.

6. A castor as claimed in claim 3, characterised in that the lower rim edge of the guide hole of said guide bush forms said latching edge for the latching of the press component.

7. A castor as claimed in claim 3, characterised in that the press component is provides with a foot pedal which serves as a release lever for the unlatching again of the press component.

8. A castor as claimed in claim 7, characterised in that the press component is fixed on the foot pedal and said ffot pedal has an oblique surface which when the press component is depressed comes to rest against a counterpressure leaf spring and in this way favours the canting of the press component and its latching against said latching edge.

9. A castor as claimed in claim 1, characterised in that the latching edge is formed by a latching leaf spring.

10. A castor as claimed in claim I, particularly in the form of a swivel castor, comprising a castor fork with a running wheel and a locking mechanism for locking said running wheel against a movement, including as locking member a press component which is axially moveable in a guide bush arranged at the castor fork and which can be pressed against the pressure of a spring into its locking position and then holds the locking mechanism in its locking position, characterised in that the press component has at a point on its periphery at least one latching notch by means of which the press component can latch in its locking position under the counterpressure of the spring against a latching edge which is formed by a latching leaf spring and is then held latched by said stressed leaf spring, and in that the latching leaf spring is extended to form a foot pedal which serves as a release lever for the unlatching again of the press component, against the pressure of said spring.

11. A castor as claimed in claim 10, characterised in that the press component has at a point on its periphery a multiplicity of latching notches.

12. A castor as claimed in claim 1, characterised in that the press component is of cylindrical form and said at least one latching notch is arranged round the cylinder periphery.

13. A castor as claimed in claim 1, characterised in that said at least one latching notch is of sawtooth form, the radially straight tooth flank serving for the latching against said latching edge.

14. A castor as claimed in claim 1, characterised in that the press component is fixed on a counterpressure leaf spring.

15. A castor as claimed in claim 1, particulary in the form of a swivel castor, comprising a castor fork with a running wheel and a locking mechanism for locking said running wheel against a movement, including as locking member a press component which is axially moveable in a guide bush arranged at the castor fork and which can be pressed against the pressure of a spring into its locking position and then holds the lock ing mechanism in its locking position, characterised in that the press component has at its periphery a sprung latching pawl which in the locked position of the press component can latch under the counterpressure of the spring against a latching edge and is then held latched by the stressed spring, and in that a release lever is provided by which the press component can be unlatched again, against the pressure of said spring.

16. A castor as claimed in claim 15, characterised in that said latching pawl has a multiplicity of latching notches arranged one above another.

117. A castor as claimed in claim 15, characterised in that the latching pawl of the press component is provided with a foot pedal which serves as said release lever for the unlatching of the press component, 

1. A castor, particulary in the form of a swivel castor, comprising a castor fork with a running wheel and a locking mechanism for locking said running wheel against a movement, including as locking member a press component which is axially moveable in a guide bush arranged at the castor fork and which can be pressed against the pressure of a spring into its locking position and then holds the locking mechanism in its locking position, characterised in that the press component has at a point on its periphery at least one latching notch by means of which the press component can latch in its locking position under the counterpressure of the spring against a latching edge and is then held latched by the stressed spring, and in that a release lever is provided by which the press component can be unlatched again, against the pressure of the spring.
 2. A castor as claimed in claim 1, particularly in the form of a swivel castor, comprising a castor fork with a running wheel and a locking mechanism for locking said running wheel against a movemeNt, including as locking member a press component which is axialy moveable in a guide bush arranged at the castor fork and which can be pressed against the pressure of a spring into its locking position and then holds the locking mechanism in its locking position, characterised in that the guide bush is arranged substantially vertically at the castor fork and the press component projects beyond the upper surface of said guide bush and forming a pushbutton for foot actuation, and in that the press component has at a point on its periphery at least one latching notch by means of which the press component can latch in its locking position under the counterpressure of the spring against a latching edge and is then held latched by the stressed spring, and in that a release lever is provided by which the press component can be unlatched again, against the pressure of the spring.
 3. A castor as claimed in claim 1, particularly in the form of a swivel castor, comprising a castor fork with a running wheel and a locking mechanism for locking said running wheel against a movement, including as locking member a press component which is axially moveable in a guide bush arranged at the castor fork and which can be pressed against the pressure of a spring into its locking position and then holds the locking mechanism in its locking position, characterised in that the press component has at a point on its periphery at least one latching notch by means of which the press component can latch in its locking position under the counterpressure of the spring against a latching edge, and in that the press component is substantially narrower than the guide hole of said guide bush and has a sufficiently large lateral play for it to be able to be canted in said guide bush by the counterpressure of the spring and thus for it to be possible to latch by said at least one latching notch against the latching edge and is then held latched by the stressed spring, and in that a release lever is provided by which the press component can be unlatched again, against the pressure of the spring.
 4. A castor as claimed in claim 2, particularly in the form of a swivel castor, comprising a castor fork with a running wheel and a locking mechanism for locking said running wheel against a movement, including as locking member a press component which is axially moveable in a guide bush arranged at the castor fork and which can be pressed against the pressure of a spring into its locking position and then holds the locking mechanism in its locking position, characterised in that the guide bush is arranged substantially vertically at the castor fork and the press component projects beyond the upper surface of said guide bush and forming a pushbutton for foot actuation, and in that the press component has at a point on its periphery at least one latching notch by means of which the press component can latch in its locking position under the counterpressure of the spring against a latching edge, and in that the press component is substantially narrower than the guide hole of the guide bush and has a sufficiently large lateral play for it to be able to be canted in said guide bush by the counterpressure of the spring and thus for it to be possible to latch by said at least one latching notch against the latching edge and is then held latched by the stressed spring, and in that a release lever es provided by which the press component can be unlatched again, against the pressure of the spring.
 5. A castor as claimed in claim 1, characterised in that the press component has at a point on its periphery a multiplicity of latching notches.
 6. A castor as claimed in claim 3, characterised in that the lower rim edge of the guide hole of said guide bush forms said latching edge for the latching of the press component.
 7. A castor as claimed in claim 3, characterised in that the press component is provides with a foot pedal which serves as a release lever for the unlatching again of the press component.
 8. A castor aS claimed in claim 7, characterised in that the press component is fixed on the foot pedal and said ffot pedal has an oblique surface which when the press component is depressed comes to rest against a counterpressure leaf spring and in this way favours the canting of the press component and its latching against said latching edge.
 9. A castor as claimed in claim 1, characterised in that the latching edge is formed by a latching leaf spring.
 10. A castor as claimed in claim 1, particularly in the form of a swivel castor, comprising a castor fork with a running wheel and a locking mechanism for locking said running wheel against a movement, including as locking member a press component which is axially moveable in a guide bush arranged at the castor fork and which can be pressed against the pressure of a spring into its locking position and then holds the locking mechanism in its locking position, characterised in that the press component has at a point on its periphery at least one latching notch by means of which the press component can latch in its locking position under the counterpressure of the spring against a latching edge which is formed by a latching leaf spring and is then held latched by said stressed leaf spring, and in that the latching leaf spring is extended to form a foot pedal which serves as a release lever for the unlatching again of the press component, against the pressure of said spring.
 11. A castor as claimed in claim 10, characterised in that the press component has at a point on its periphery a multiplicity of latching notches.
 12. A castor as claimed in claim 1, characterised in that the press component is of cylindrical form and said at least one latching notch is arranged round the cylinder periphery.
 13. A castor as claimed in claim 1, characterised in that said at least one latching notch is of sawtooth form, the radially straight tooth flank serving for the latching against said latching edge.
 14. A castor as claimed in claim 1, characterised in that the press component is fixed on a counterpressure leaf spring.
 15. A castor as claimed in claim 1, particulary in the form of a swivel castor, comprising a castor fork with a running wheel and a locking mechanism for locking said running wheel against a movement, including as locking member a press component which is axially moveable in a guide bush arranged at the castor fork and which can be pressed against the pressure of a spring into its locking position and then holds the locking mechanism in its locking position, characterised in that the press component has at its periphery a sprung latching pawl which in the locked position of the press component can latch under the counterpressure of the spring against a latching edge and is then held latched by the stressed spring, and in that a release lever is provided by which the press component can be unlatched again, against the pressure of said spring.
 16. A castor as claimed in claim 15, characterised in that said latching pawl has a multiplicity of latching notches arranged one above another.
 17. A castor as claimed in claim 15, characterised in that the latching pawl of the press component is provided with a foot pedal which serves as said release lever for the unlatching of the press component. 